Image projector, projected image pattern, laser driver, imaging device

ABSTRACT

Image projection apparatus wherein, a focusing lens is controlled when a shutter is operated so that a contrast signal, obtained when a luminance signal from a camera signal processing circuit is supplied to an auto focusing detection circuit, may become maximum. A laser diode is driven to generate laser beams that are condensed into parallel laser beams by a condenser. These parallel laser beams are applied to a hologram plate and thereby diffracted. The diffracted laser beams interfere with each other, to produce a hologram image with sufficient contrast. Therefore, satisfactory focusing can be made in an auto focus mode of the contrast detection system or in a manual focus mode.

TECHNICAL FIELD

The present invention relates to an image projection apparatus, aprojection image pattern, a laser drive apparatus and a camera apparatusfit for use in an electronic still camera, for example. Particularly,the present invention relates to an image projection apparatus, aprojection image pattern, a laser drive apparatus and a camera apparatuseach of which helps focusing adjustment when a user takes a picture, forexample, in the dark.

BACKGROUND ART

When a user takes a picture by a still camera, for example, in the darkbecause it is difficult for a user to visually confirm an object, theobject cannot be brought into focus by an auto focus camera, forexample, of a contrast detection type. It is also difficult to bring theobject into focus in a manual focus mode. To solve this problem, therehas been employed so far a method which enables an auto focusingoperation by irradiating the object with an auxiliary floodlight such asan LED. According to this method, however, when an object has lowcontrast, it used to be difficult to bring the object into focus.

On the other hand, for example, a floodlight for producing a largeoutput required for obtaining the brightness enough to focus on theobject consumes large electric power and thus produces such a great dealof heat that the floodlight cannot be used near the object.Alternatively, there is known, for example, a method in which light iscondensed by a lens to floodlight an object. However, when light iscondensed into a narrow area in order to increase the brightness of anobject, if a user takes a picture using a wide-angle lens, then afloodlighted area will be too narrow to make focusing easily.Conversely, if the floodlighted area is made so wide as corresponds tothat in the wide-angle photographing, a sufficient brightness of theobject cannot be obtained disadvantageously.

Further, while there is employed an auxiliary floodlight in which a lensand a slit are placed in front of an LED or an electric bulb, etc. toproject an image of the slit onto the object, a projected image has lowcontrast, so that satisfactory focusing is made difficult. Moreover,according to this method, light loss is unavoidably produced in thefloodlight due to the slit, and hence electric power consumption forobtaining a necessary quantity of light is extremely large. As a result,it is difficult for the above-mentioned auxiliary floodlight to beincorporated into, for example, a small electronic still camera anddriven by a power supply such as a built-in battery.

Aside from these prior arts, there has been proposed an image projectionapparatus in which an arbitrary hologram reproduced image is projectedby using, for example, a laser light source and a hologram plate. Suchhologram reproduced image can enhance contrast of a projected image.Accordingly, it is conceived that this hologram reproduced image isprojected onto an object to be made use of focusing. That is to say, thedetection in the manual focus mode or in the auto focus mode isperformed using the hologram reproduced image that is projected onto theobject.

However, the image projection apparatus is such that a hologram plate isadded to the existing so-called “laser pointer”, the structure of whichis shown in FIGS. 14A and 14B, for example. Specifically, as shown inFIG. 14A, a laser light source 71 for generating light of diffused laserbeams and a condenser 72 for converting the light of diffused laserbeams to light of parallel laser beams are provided within a lens barrel70. The light of parallel laser beams converted by this condenser 72 isused as a laser pointer for indicating an arbitrary point and so on.

A hologram plate 73 is provided within a lens barrel 74 which is fittedonto the lens barrel 70. Then, when the light of parallel laser beams isapplied to this hologram plate 73, a hologram reproduced image is formedand projected onto the object. However, in this image projectionapparatus, the laser light source 71 and the condenser 72 are integratedwith each other as a single unit by the lens barrel 70, and the hologramplate 73 of the lens barrel 74 is added to this unit thus formed. Whenthe lens barrel 74, for example, is broken, there is a risk that onlythe hologram plate 73 may be detached from the unit.

Accordingly, when the hologram reproduced image is projected onto theobject to be used for focusing as described above, if only the hologramplate 73 is detached from the unit and the light of parallel laser beamsfrom the condenser 72 is directly applied to the object as shown in FIG.14B, then the object, for example, a man will feel discomfort due to adazzling light of parallel laser beams if he sees it. When the hologramplate 73 is present, the hologram reproduced image is formed and hencelight of laser beams is diffused, so that the discomfort given to a manwill be alleviated.

The present invention is made in view of the aforesaid points and theproblems to be solved is as follows: When a user takes a picture by astill camera in the dark, for example, it is difficult for the user tofocus in the auto focus mode of the contrast detection system or in themanual focus mode. On the other hand, the camera apparatus using theconventional auxiliary floodlight does not allow a satisfactory focusingto be performed. Moreover, because the conventional auxiliary floodlightconsumes large power, it cannot be incorporated into a small electronicstill camera for use.

Furthermore, the image projection apparatus using, for example, thelaser light source and the hologram plate has a risk that, when thehologram plate is detached and so forth, a man as an object will feeluncomfortable very much due to a dazzling light of parallel laser beamsif he sees it.

DISCLOSURE OF INVENTION

The present invention seeks to facilitate the focalization when a usertakes a picture, for example, in the dark. For this purpose, the presentinvention is arranged to project onto the object the hologram reproducedimage which is obtained by using the laser light source and the hologramplate. In this connection, there will be disclosed below an imageprojection apparatus, a projection image pattern, a laser driveapparatus and a camera apparatus according to the present invention.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing an embodiment of an image projectionapparatus and a camera apparatus according to the present invention.

FIG. 2 is a flow chart for explaining an operation of the embodiment.

FIG. 3 is a flow chart for explaining another operation of theembodiment.

FIG. 4 is a diagram showing an embodiment of a projection image patternaccording to the present invention.

FIG. 5 is a graph for explaining the pattern.

FIG. 6 is a flow chart showing an operation of a laser drive apparatusaccording to an embodiment of the present invention.

FIG. 7 is a flow chart showing an operation of a laser drive apparatusfor adjusting an output of a laser light source according to anotherembodiment of the present invention.

FIG. 8 is a diagram showing environment for the laser drive apparatus toadjust the output of the laser light source.

FIG. 9 is a block diagram showing a specific circuit of the laser driveapparatus according to an embodiment of the present invention.

FIG. 10 is a flow chart showing an operation of a laser drive apparatusaccording to still another embodiment of the present invention.

FIGS. 11A and 11B are waveform diagrams of a pulse signal for explaininga laser drive apparatus according to yet another embodiment of thepresent invention.

FIGS. 12A and 12B are specific structure diagrams of an image projectionapparatus and a camera apparatus according to the present invention.

FIG. 13 is a diagram for explaining the above embodiments of the presentinvention.

FIGS. 14A and 14B are structure diagrams of conventional imageprojection apparatus.

BEST MODE FOR CARRYING OUT THE INVENTION

An image projection apparatus, a projection image pattern, a laser driveapparatus and a camera apparatus according to the present invention willbe described below with reference to the drawings, FIG. 1 of which is ablock diagram showing structures of an image projection apparatus and acamera apparatus according to an embodiment of the present invention.

Referring to FIG. 1, image light from an object (not shown), forexample, is condensed through a main lens 1, a zoom lens 2 and afocusing lens 3 and an object image is brought into focus on a chargecoupled device (hereinafter abbreviated to “CCD”) 4 serving as an imagepickup means. This object image is photoelectrically converted by theCCD 4 and further converted into a digital signal by a sample/hold andgain control (hereinafter abbreviated to “S/H & AGC) circuit 5.

This digital signal is further converted into a chrominance signal and aluminance signal by a camera signal processing circuit 6 and thenoutputted to a signal recording system, not shown. The luminance signalfrom this camera signal processing circuit 6 is supplied to an autofocusing (hereinafter abbreviated to “AF”) detection circuit 7, in whicha contrast signal necessary for AF is generated using this luminancesignal. Then, the contrast signal thus generated is supplied to amicrocomputer (hereinafter abbreviated to “micon”) 8 for use in controloperations.

Thus, if the micon 8 detects that a shutter release 9, for example, ishalf depressed, then the micon controls the focusing lens 3 so as tomake the above-mentioned contrast signal maximum in level for AFoperation. The focusing lens 3 may be controlled by sending an amountsignal to a motor driver circuit 10 for driving a focus motor 11.Similarly, the zoom lens 2 may be controlled by sending an amountcontrolling signal to the motor driver circuit 10 for driving a zoommotor 12.

A control signal is supplied from the micon 8 to a laser driver 13,whereby a laser diode 14 is driven to generate light of laser beams onlywhile this control signal is supplied from the micon to the laserdriver. The light of laser beams thus generated is condensed by acondenser 15 into light of parallel laser beams and the light ofparallel laser beams is applied to a hologram plate 16, in which thelight of parallel laser beams is diffracted by a hologram provided inthe hologram plate 16. Then, the laser beams thus diffracted are causedto interfere with each other, thereby making a hologram reproduced image17 reproduced.

As a result, this hologram reproduced image 17 can be projected onto theobject which lies , for example, in the optical axis direction of themain lens 1. In this case, if the hologram reproduced image 17 iscomposed of segments, then an area where the image is projected can bedecreased as compared with a projection range. Thus, an image with highcontrast can be projected to increase illuminance of the object. Inother words, by projecting the image with high contrast onto the object,satisfactory focusing can be done with ease.

Additionally, the means (apparatus) itself for projecting theabove-mentioned hologram reproduced image 17 is readily available as anauxiliary device for use with the existing laser pointer, for example,which apparatus can easily be formed by applying such device thereto.Because the laser diode 14 for use with such laser pointer can be drivenwith extremely small power consumption, such laser diode can beincorporated, for example, into a small electronic still camera, and caneasily be driven by a built-in battery and the like.

There is further provided a manual switch 18 for controlling a manner inwhich the hologram reproduced image 17 is projected onto the object.When this manual switch 18 is operated, a high potential signal issupplied to the micon 8. Further, a control signal from the micon 8 issupplied to a flash device 19 so that the light emission of the flashdevice 19 may be controlled by this control signal as needed. Moreover,data corresponding to measured values and controlled values generatedwithin the micon 8 are stored in a nonvolatile memory (e.g., EEPROM) 20.

FIG. 2 shows a flow chart of exemplary processings executed when theauto focusing operation is performed by the above-mentioned apparatus.Specifically, in FIG. 2, following the start of operation, it is firstdetermined at a step [1] whether or not the shutter release 9 is halfdepressed. If it is not depressed (No), then this step [1] is repeated.If it is determined at the step [1] that the shutter release 9 isdepressed (Yes), then the laser diode 14 is driven at a step [2] tostart the projection of laser beams.

At a step [3], the AF operation is performed and it is determined at astep [4] whether or not the AF operation is over. If the AF operation isnot over (No), then the steps [2], [3] are repeated. If it is determinedat the step [4] that the AF operation is over (Yes), then the laserdiode 14 is deactivated to halt the projection of light of laser beams.At a step [6], for example, the flash device is activated to capture animage (photograph) and the processing is stopped.

The processings are executed in this manner when the above-mentionedapparatus is applied to the auto focusing operation. In this case, whilethe AF operation is performed at the step [3], the hologram reproducedimage 17 which is reproduced at the step [2] is projected onto theobject, and hence an extremely satisfactory AF operation can beperformed using this hologram reproduced image 17. Because theprojection of this hologram reproduced image 17 is halted at the step[5] when the image is captured (photographed), this hologram reproducedimage will never hinder the user from taking a picture.

FIG. 3 is a flow chart showing exemplary processings executed when theabove-mentioned apparatus is used in the manual focus mode. In thiscase, for example, when the manual switch 18 of the above-mentionedapparatus is operated, the processing is started. Following the start ofoperation, at a step [11], the laser diode 14 is driven first to startthe projection of light of laser beams. It is determined at the nextstep [12] whether or not the shutter release 9 is half depressed.

If it is determined at the step [12] that the shutter release 9 is notdepressed (No), then the manual focus mode is not over, and hence thesteps [11], [12] are repeated. On the other hand, if the manual focusmode is over and it is determined at the step [12] that the shutterrelease 9 is depressed (Yes), then the laser diode 14 is deactivated tohalt the projection of light of laser beams at a step [13]. Then, animage is captured (photographed) at a step [14] and the processing isstopped.

The processings are executed in this manner, when the above-mentionedapparatus is used in the manual focus mode. In this case, because thehologram reproduced image 17 which is reproduced at the step [11] isprojected onto the object, a user can make an extremely satisfactorymanual focusing by visually confirming this hologram reproduced image17. Because this hologram reproduced image 17 is turned off at the step[13] when the image is captured (photographed), this hologram reproducedimage will never hinder the user from taking a picture.

Accordingly, in this embodiment, because the hologram reproduced imageobtained by using the laser light source and the hologram plate isprojected onto the object, the hologram reproduced image havingsufficient contrast can be projected onto the object by small powerconsumption. Thus, satisfactory focusing can be done in the auto focusmode of the contrast detection system or in the manual focus mode. Atthe same time, this apparatus can easily be incorporated into, forexample, a small electronic still camera.

As described above, when a user takes a picture by a still camera, forexample, in the dark, it is difficult for the user to focus in the autofocus mode of the contrast detection system or in the manual focus mode.On the other hand, the user not can make sufficient focusing with thecamera apparatus using the conventional auxiliary floodlight.Furthermore, the conventional auxiliary floodlight consuming a largeamount of electric power cannot be incorporated into a small electricstill camera or the like. According to the present invention, theseproblems can be overcome with ease.

In the above-mentioned apparatus, as the projection image pattern of thehologram reproduced image for use in projection, such one shown in FIG.4 is used, for example. FIG. 4 shows a projection image patternaccording to an embodiment of the present invention. As shown in FIG. 4,the projection image pattern is comprised of at least one or a pluralityof first to fifth segments A to E on each of which a predeterminednumber of light spots are arrayed in a straight line. The first segmentA is provided at the center of the projection image at an angle ofapproximately 45 degrees with horizontal and vertical axes of the imagepickup plane.

There are provided four second segments B₁ to B₄, at right angles withthe first segment A, at each vertex of a square X₁ which circumscribes acircle that is centered at the center of the first segment A and has apredetermined length of diameter a (X₁ is shown by broken lines: thesquare shown by broken lines is not a projection image pattern andhereinafter the same applies.). There are further provided eight thirdsegments C₁ to C₈, in parallel with the first segment A, at each vertexand at a midpoint in each side of a square X₂ (shown by broken lines)which circumscribes a circle that is centered at the center of the firstsegment A and has a diameter 2 a twice the predetermined length a.

There are also provided twelve fourth segments D₁ to D₁₂, at rightangles with the first segment A, at each vertex and at points trisectingeach side of a square X₃ (shown by broken lines) which circumscribes acircle that is centered at the centre of the first segment A and has adiameter 3 a three times the predetermined length a. There are furtherprovided four fifth segments E₁ to E₄, in parallel with the firstsegment A, at a midpoint of each side of a square X₄ (shown by brokenlines) which circumscribes a circle that is centered at the center ofthe first segment A and has a diameter 4 a four times the predeterminedlength a. In this way, the projection image pattern composed oftwenty-nine segments in total is formed.

In this projection image pattern, each of the segments A to E iscomprised of, for example, a fifteen light spots, arrayed in a straightline. The length of these segments A to E are set at 0.8 degree by aprojection angle, for example. The central spot of the arrayed lightspots is removed from the segment A. Specifically, a hologram for makingthe segments A to E shown in FIG. 4 into a reproduced image is found bycalculation, and the hologram based upon this calculation is provided onthe hologram plate 16.

The circle having a diameter of the predetermined length a, which isinscribed in the square X₁, is set at, e.g. three degrees by aprojection angle. As a result, a projection angle of the circle which isinscribed in the square X₂ will be six degrees; a projection angle ofthe circle which is inscribed in the square X₃ will be nine degrees; anda projection angle of the circle which is inscribed in the square X₄will be twelve degrees. In this case, a pattern within the circle whichis inscribed, e.g. in the square X₂ is comprised of seven segmentssubstantially. Thus, an output of the laser diode 14 is set so that thequantity of heat produced when light corresponding to the seven segmentsstrikes man's retina may be less than the value of safety standards.

Therefore, according to this embodiment of the projection image pattern,even if positions of view points are moved under the respectiveprojection angles, the heat generated will never exceed the value ofsafety standards. FIG. 5 is a graph showing the relation between themaximum powers and receptive angles with respect to heat generated,which was found by simulation. As this figure shows, even continuousgeneration of laser beams conforms to the safety standards of 1000second AEL of the class 1 of the JIS.

Moreover, according to the embodiment of the above-mentioned projectionimage pattern, because the angles of adjacent segments are alternatelychanged from each other, the substantial space between the segments canbe reduced by the distance of half the length of the segment. Therefore,when the detection range of the auto focus is, e.g. about 3 degrees interms of the projection angle, even if the optical axis of a camera lensis not coincident with the center of the projection image pattern, it ispossible to remove such a risk that no segment will fall within thedetection range.

Furthermore, in the above embodiment of the projection image pattern,the central light spot is removed from the light spots forming the firstsegment A located at the center. As a consequence, although in thehologram reproduced image zero-order light may sometimes be generated atthe center of the image in addition to an original image pattern, abrightness of the light spot at the center of the first segment A can beprevented from being raised due to such zero-order light, thus allowinga satisfactory detection to be done. Even if the light spot at thecenter of the first segment has no brightness, there is no risk that thedetection, e.g. in the auto focus mode may be interfered with.

In the above-mentioned apparatus, the laser diode 14 is driven as shownin FIG. 6. That is, FIG. 6 is a flow chart showing exemplary operationsof the laser drive apparatus according to an embodiment of the presentinvention.

Referring to FIG. 6, upon the start of operation, it is first determinedat a step [21] whether or not the shutter release 9 is half depressed.If it is depressed (Yes), it is determined at a step [22] whether or nota value of “on-counter” of an arbitrary register is less than 100seconds. If the on-counter value is less than 100 seconds (Yes), apredetermined value is added to the on-counter value at a step [23]. Avalue of an “off-counter” of an arbitrary register is reset to zero at astep [24], and the application of light of laser beams is maintained ata step [25].

It is further determined at a step [26] whether or not a command formaking the power supply off is issued. If such command for making thepower supply off is issued (Yes), then the operation comes to an end(End). If it is determined that no command for making the power supplyoff is issued (No), then the operation is returned to the step [21]. Ifit is determined at the step [21] that the shutter release 9 is notdepressed (No) and if it is determined at the step [22] that theon-counter value is not less than 100 seconds (No), then it isdetermined at a step [27] whether or not the off-counter value is lessthan five seconds.

If it is determined at the step [27] that the off-counter value is lessthan five seconds (Yes), then a predetermined value is added to theoff-counter value at a step [28]. If it is determined at the step [27]that the off-counter value is not less than five seconds (No), then theon-counter value is reset to zero at a step [29]. After the steps [28]and [29] have been finished, the application of light of laser beams isstopped at a step [30], and it is determined at the step [26] whether ornot the command for making the power supply off should be issued.

Accordingly, in this flow chart, when the on-counter value goes greaterthan 100 seconds, the application of light of laser beams is stopped.Besides, while the off-counter value remains less than five seconds, theon-counter value is not reset. Therefore, the apparatus is operated sothat duration in which the application of light of laser beams isstopped may always be five seconds or longer. Thus, when the light oflaser beams, for example, is applied continuously, an output of theapparatus can be prevented from falling due to heat and the like. As aconsequence, it is possible to eliminate a radiator plate or the likethat has so far been used as a conventional countermeasure against theheat generation.

Moreover, in the above-mentioned apparatus, an output of the laser diode14 is adjusted as shown in FIGS. 7 and 8. Specifically, FIG. 7 is a flowchart showing operations of the laser drive apparatus to adjust theoutput of the laser diode 14 according to another embodiment of thepresent invention. FIG. 8 shows an environment under which the output ofthe laser diode is adjusted by the laser diode drive apparatus.

Referring to FIG. 8, a screen 200 is attached to one of wall surfaces ofa box 100 the inside of which is painted in black. The above-mentionedcamera apparatus is disposed through an opening 300 provided on the wallsurface opposite to the screen 200. Then, the above-mentioned hologramreproduced image 17 is projected onto the screen 200 and the projectedimage on this screen 200 is picked up by the CCD 4. Further, the imagepicked-up output from this CCD 4 is detected to adjust the output fromthe laser diode 14.

Referring to FIG. 7, upon the start of adjustment operation, a controlvalue (DA) supplied from the micon 8 to the laser driver 13 is set as aninitial value at a step [31], and the lens position is set for adistance between the camera apparatus disposed through the opening 300and the screen 200 at a step [32]. Then, at a step [33], theabove-mentioned control value (DA) is supplied through a DA output fromthe micon 8 to the laser driver 13. At a step [34], the laser diode 14starts to be driven.

In this way, the laser diode 14 is driven in accordance with thepredetermined initial value, the hologram reproduced image 17 based uponthe laser output according to this initial value being projected ontothe screen 200, and this projected image being picked up by the CCD 4.Then, at a step [35], an automatic exposure (AE) detected value (AEDATA) is detected from the image picked-up output and compared with anAE target value (AE TARGET) at a step [36]. If the two values are notequal to each other (No), then, a control value (DA) is calculated at astep [37].

Specifically, at the step [37], a new control value (DA) is calculatedfrom an expression, e.g. DA=DA×(AE TARGET)÷(AE DATA) and the resultantvalue is returned to the step [33]. This operation will be repeateduntil (AE DATA)=(AE TARGET) is satisfied at the step [36]. Then, whenthe two values become equal to each other (Yes), the control value (DA)is stored in the nonvolatile memory 20 at a step [38] and the operationcomes to an end.

In this manner, the value which is used to adjust the dispersion of theoutput from the laser diode 14 is stored in the nonvolatile memory 20.In actual practical use, the control value (DA) for driving the laserdiode 14 is calculated based upon the value stored in this memory 20 andtaking other conditions and the like into consideration. In other words,when a user takes a picture, the stored value is read out from thismemory 20 to be used as a basic value for adjustment. At the same time,information on stop, zoom position and the like is considered to controlthe output of the laser diode 14.

The dispersion of the output of the laser diode 14 can be adjusted byusing not only the above-mentioned automatic exposure detected value butalso a contrast detected value and the like. For example, the controlvalue (DA) in which the contrast detected value forms the target valueis stored in the memory. Moreover, if not only the above-mentionedcontrol value but also the detected value itself and other measuredvalues are stored in the memory 20, then such stored values can be used,for example, to check products in manufacturing, and also to check theirperformances when services or repairs are made after the products havebeen shipped.

Accordingly, in this embodiment, the output of the laser diode 14 aswell as the sensitivity of the CCD 4 is adjusted. Specifically, whilethe output of the laser diode 14 according to the control value hasdispersion between individual products, the sensitivity of the CCD 4also fluctuates similarly about 20 percent. Accordingly, by adjustingthe output of the assembled camera apparatus using the image picked-upoutput of the CCD 4, the adjustment which absorbs both the dispersionand fluctuation can be carried out.

In the above-mentioned apparatus, the laser driver 13 has a specificstructure as shown in FIG. 9. FIG. 9 is a block diagram showing aspecific circuit of a laser drive apparatus according to an embodimentof the present invention.

Referring to FIG. 9, the laser diode 14 is driven by a power supply of,e.g. 5V, and other circuits including the micon 8 are driven by a powersupply of 3.2V. An output signal from the micon 8 is supplied through aswitching transistor 51 to a switching transistor 52 provided at thepower supply line of 5V, whereby the power supply of 5V is turned on andoff. A voltage from the power supply of 5V which is turned on and off issupplied through a transistor 53 to the laser diode 14.

A photodiode 54 is provided in the vicinity of this laser diode 14. Anoutput from this photodiode 54 is supplied to a non-inverting inputterminal of an operational amplifier 55, whereas a control value fromthe micon 8 is supplied to an inverting input terminal of theoperational amplifier 55 through a digital-to-analog converter (DAC) 56.An output from this operational amplifier 55 is supplied to the base ofthe transistor 53. This causes the output of the laser diode 14 to beadjusted so that the output of the photodiode 54 may be kept at adesired value.

An output from the switching transistor 52 is supplied to a falling edgetrigger input terminal of a monostable multivibrator (hereinafterabbreviated to “mono-multi”) 57. A Q output of this mono-multi 57 issupplied through the transistor 58 to the base of a transistor 59. Asignal obtained at the collector of this transistor 59 is supplied tothe base of a transistor 60 connected between the 5V power supply lineafter the switching transistor 52 and the base of the transistor 53.

Thus, in this circuit, when the laser diode 14 is continuously driven,for example, by the output continuously generated from the switchingtransistor 52, if the time period driving this laser diode exceeds aninverting time of the mono-multi 57, then the transistor 58 is turnedon, the transistor 59 being turned off and the transistor 60 beingturned on. As a result, the base potential of the transistor 53 rises tomake and the transistor 53 turned off, whereby such continuous drivingof the laser diode 14 is stopped.

Further, in the above-mentioned circuit, the output of the photodiode 54is supplied to an A/D converting input terminal of the micon 8 whichmonitors the output of the photodiode 54 to operate, for example, asshown in FIG. 10.

FIG. 10 is a flow chart showing operations of a laser drive apparatusaccording to a still another embodiment of the present invention.Referring to FIG. 10, it is first determined at a step [41] whether ornot the shutter release 9 is half depressed. If the shutter release isdepressed (Yes), it is determined at a step [42] whether or not amonitor voltage obtained from the photodiode 54 is equal to an arbitraryreference voltage. Then, if the monitor voltage is equal to thereference voltage (Yes), the application of light of laser beams ismaintained at the following step [43].

On the contrary, if it is determined at the step [41] that the shutterrelease 9 is not depressed (No) or if it is determined at the step [42]that the monitor voltage is not equal to the reference voltage (No),then the application of light of laser beams is stopped at a step [44].Further, it is determined at a step [45] whether or not a command formaking the power supply off is issued. If such command for making thepower supply off is issued (Yes), then operations come to an end. If nocommand for making it off is issued (No), then the operation is returnedto the step [41].

Accordingly, in this embodiment, when the monitor voltage obtained fromthe photodiode 54 becomes equal to the arbitrary reference voltage, theapplication of light of laser beams is stopped. In other words, thegeneration of light of laser beams is stopped, provided that the outputof the monitor means exceeds an arbitrary tolerance limit. This makes itpossible to remove such a risk that the laser diode 14 may be broken ordegraded in durability by an abnormal driving of the laser diode 14.

Moreover, in the specific circuit of the laser drive apparatus shown inFIG. 9, a pulse signal, for example, as shown in FIGS. 11A and 11B, isoutputted from the micon 8, and the laser diode 14 is driven accordingto this pulse signal. FIGS. 11A and 11B are waveform diagrams of pulsesignals for explaining a laser drive apparatus according to yet anotherembodiment of the present invention.

In this connection, the micon 8 can form a pulse signal with accuracy,of for example, 0.8 μsec by using a counter, and can control the pulsewidth, for example, by the 0.16 msec. Moreover, a peak output of thepulse signal can be adjusted, for example, in a range of 0 to 3 mW bythe 0.1 mW. Accordingly, for example, based upon the value that isstored in the memory 20 in the above-mentioned operations shown in FIG.7, the peak output of the pulse signal may be determined and the pulsewidth may be controlled in consideration of other conditions.

As shown in FIG. 11A, based upon the value stored in the memory 20, theamplitude of the pulse signal is determined to be ,for example, 2.5 mW.Moreover, the pulse width of each pulse may be controlled depending onwhether the built-in flash device 19 or an external flash device is usedor not. Specifically, for example, when the built-in flash device 19 isin use, the pulse width of the pulse signal is controlled to be 5 msec,and when the external flash device is in use, because long distance toan object is assumed, then the pulse width is controlled to be 10 msec.

Furthermore, when the photography system is based upon the NTSC system,the micon forms the pulse signal at a cycle of 33 msec synchronized withthe frame. Because the auto focusing operation can be controlled within50 frames, it is designed that 50 pulses are generated during oneoperation at maximum. In this manner, the output of the laser diode 14is adjusted. Such operations are executed by software of the micon 8.

FIG. 11B shows a waveform of a pulse signal generated when the halfdepression of the shutter release 9 is repeated. Specifically, when auser takes a picture in a normal mode, because it takes approximatelyfour seconds to store image data in a memory device, an interval of 4seconds is inevitably formed. Even if the shutter release 9 is halfdepressed very quickly, it is arranged that an interval of one second isformed. Such operations are also executed by software of the micon 8 andintervals of 0 to 4 seconds are set by the 0.25 second, for example,based upon the values stored in the memory 20.

Moreover, when the laser diode is driven according to the pulse signalas described above, if the inverting time of the above-mentionedmono-multi 57 shown in FIG. 9 is set to be, for example, 33 msec, thenthe generation of light of laser beams can be stopped when the fallingedge of the pulse signal does not occur. Thus, when the means foradjusting a quantity of light of laser beams malfunctions, the laserdiode 14 can be stopped from being driven. This makes it possible toremove the risk that the laser diode 14 may be damaged or less durable.

Therefore, in this embodiment, the quantity of light of laser beams canbe adjusted satisfactorily by driving the laser light source accordingon the pulse signal having an arbitrary pulse width. Moreover, thequantity of light of laser beams can also be adjusted by controlling thepulse width depending on the presence or absence of the built-in flashdevice 19 or the external flash device. Furthermore, when the means foradjusting the quantity of light of laser beams malfunctions, the drivingof the laser diode 14 can be stopped to remove the risk that the laserdiode 14 may be broken or less durable.

By applying the above-mentioned image projection apparatus, theprojection image pattern or the laser drive apparatus to the cameraapparatus according to the present invention, the hologram reproducedimage having a sufficient contrast can be projected onto the object withsmall power consumption, so that satisfactory focusing can be attained.At the same time, these apparatus can easily be incorporated into asmall electronic still camera and the like.

As described above, the image projection apparatus of the presentinvention comprises the laser light source for generating light of laserbeams and the hologram plate. By projecting onto the object the hologramreproduced image which is obtained by applying light of laser beams tothe hologram plate, the hologram reproduced image having good contrastcan be projected onto the object with small power consumption, thusallowing satisfactory focusing to be performed. Also, this apparatus caneasily be incorporated into a small electronic still camera and thelike.

Further, according to the projection image pattern of the presentinvention, by employing the above-mentioned pattern of FIG. 4, heatproduced can be prevented from exceeding the safety standards limit,even if the position of the view point is moved under the respectiveprojection angles. At the same time, because the substantial spacebetween the segments can be reduced by a distance which is half a lengthof the segment, even if the optical axis of the camera lens is notcoincident with the center of the projection image pattern, there can beremoved such a risk that a state in which no segment is captured withinthe detection range may occur.

Moreover, according to the laser drive apparatus of the presentinvention, because this laser drive apparatus includes the laser lightsource for generating light of laser beams and the laser light source isstopped from generating the light of laser beams for a fixed time periodor longer, on condition that the duration of emitting the light of laserbeams exceeds the predetermined time period, for example, when the lightof laser beams is applied continuously, the output can be prevented fromfalling due to heating or the like. Thus, a radiator plate that has sofar been used as a conventional countermeasure against heat generationcan be dispensed with.

Furthermore, the laser drive apparatus of the present invention includesthe laser light source for generating light of laser beams, the meansfor adjusting the quantity of light of laser beams and the camera means,and further comprises the memory means for storing therein theadjustment value found according to an output of the camera means whichhas taken the image under previously projected light of laser beams.Thus, the output of the laser light source as well as the sensitivity ofthe camera means can be adjusted by adjusting the quantity of light oflaser beams based upon the stored adjustment value. In other words, theadjustment absorbing dispersions of the output and the sensitivity canbe carried out.

Furthermore, the laser drive apparatus of the present invention includesthe laser light source for generating light of laser beams and themonitor means for detecting light of laser beams, and is arranged sothat the laser light source may be stopped from generating light oflaser beams on condition that an output of the monitor means exceeds thearbitrary tolerance limit. Thus, it is possible to remove the risk thatthe laser light source may be damaged or less durable by an abnormaldriving of laser light source.

Moreover, the laser drive apparatus of the present invention includesthe laser light source for generating light of laser beams and the meansfor adjusting the quantity of light of laser beams, and is arranged sothat the quantity of light of laser beams may be adjusted by driving thelaser light source using the pulse signal having the arbitrary pulsewidth. Thus, the quantity of light of laser beams can be adjustedsatisfactorily, and also the quantity of light of laser beams can beadjusted depending on the presence or absence of the built-in flashdevice, so that it is possible to remove the risk that the laser lightsource may be broken or degraded in durability.

Furthermore, the camera apparatus of the present invention includes theprojection means having the laser light source and the hologram plate,for projecting onto the object a hologram reproduced image which isobtained by applying light of laser beams from the laser light source tothe hologram plate. Thus, the hologram reproduced image having goodcontrast can be projected onto the object with small power consumption,thereby allowing satisfactory focusing to be attained. At the same time,this apparatus can easily be incorporated into a small electronic stillcamera or the like.

In short, the above-mentioned camera apparatus has the advantageouseffects as follows:

{circle around (1)} The focusing is enabled in the AF mode even oncondition that the illuminance of an object is low.

{circle around (2)} Even an object with low contrast can be brought intofocus in the AF mode.

{circle around (3)} Because light of laser beams with high contrast isprojected on an object, the focusing is enabled in the auto focus modewith higher accuracy than before.

{circle around (4)} The long-distance projection, which has heretoforebeen difficult to be made with a conventional auxiliary floodlighthaving low output, becomes possible.

{circle around (5)} Because of a projecting efficiency several times ashigh as that of the conventional auxiliary floodlight, a low-outputprojection apparatus can be used for obtaining a sufficient illuminance,so that energy consumption thereof is reduced to a reciprocal of severalof conventional energy consumption.

{circle around (6)} Because an effective projected area is small, it isless possible that those who are photographed will feel dazzled.

{circle around (7)} An object with low illuminance and low contrast,which has been hard to be brought into focus in the conventional manualfocus mode, can be brought into focus with ease.

{circle around (8)} The projection compatible to both of wide-angle lensmode and telephoto lens mode, which has so far been difficult to be madewith the conventional auxiliary floodlight, becomes possible.

FIGS. 12A and 12B show specific structures of the image projectionapparatus and the camera apparatus according to the present invention.Referring to FIG. 12A, only a laser diode 14 for generating light ofdiffused laser beams is provided within a laser-support frame 21. Acondenser 15 which converts light of diffused laser beams to light ofparallel laser beams is provided within a lens-support frame 22 which isfitted on the laser-support frame 21. At the same time, a hologram plate16 is attached to the lens-support frame, e.g. by a retaining ring 23.Thus, these elements are integrally formed as a single unit.

After a clearance between the laser-support frame 21 and thelens-support frame 22 is adjusted, these laser- and lens-support frames21 and 22 are fixed by an adhesive and the like. Then, these laser- andlens-support frames 21 and 22 are attached to a predetermined positionof a camera housing 25 through a transparent acrylic cover 24. In otherwords, a window covered by the transparent acrylic cover 24 is providedat the predetermined position of the camera housing 25 and the laser-andlens-support frames 21 and 22 are attached to this transparent acryliccover 24.

As a result, when the laser diode 14 is driven in this state, light ofthe diffused laser beams thus generated is converted into light ofparallel laser beams by the condenser 15 and the light of parallel laserbeams is applied to the hologram plate 16, thereby causing a hologramreproduced image (not shown) to be produced. Then, this hologramreproduced image is projected onto the object through the transparentacrylic cover 24 provided at the predetermined position of the camerahousing 25.

Accordingly, in this embodiment, the condenser 15 and the hologram plate16 are integrated into one body unit. Thus, for example, when thelens-support frame 22 is broken as shown in FIG. 12B, both of thecondenser 15 and the hologram plate 16 are detached from the laser diode14. In other words, when the lens-support frame 22 is broken and thehologram plate 16 is detached from the laser diode, the condenser 15 isalso detached from the laser diode 14 at the same time.

In this case, because only the light of diffused laser beams isgenerated by the laser diode 14 from which the condenser lens 15 isdetached, even if the light of diffused laser beams is directly appliedto an object, when the object is, for example, a man, there will be norisk that a man will feel discomfort due to the dazzling light ofparallel laser beams. Therefore, according to this embodiment, even ifthe hologram plate is detached from the laser diode, there can beremoved such a risk that a man may feel discomfort due to the dazzlinglight of laser beams.

As described above, when a user takes a picture by a still camera in thedark, or the like, it is very difficult to focus in the auto focus modeof the contrast detection system or in the manual focus mode. On theother hand, the image projection apparatus employing the laser lightsource and the hologram plate involves a risk that a man as an objectwill feel uncomfortable very much if he sees the dazzling light ofparallel laser beams when the hologram plate is detached from the laserdiode. According to the present invention, these problems can beovercome with ease.

In the above-mentioned apparatus, as shown in FIG. 13, for example, whena small hologram image for taking a picture in the telephoto lens modeand a large hologram image for taking a picture in the wide-angle lensmode are both projected onto the object at the same time, it will bepossible to make adapt for both of the wide range projection and thetelephotograph projection. Additionally, in FIG. 13, there are projectedsuch hologram images that a projection angle of an inner circle is setat about 5 degrees and a projection angle of an inner circle is set atabout 20 degrees. In addition, when the hologram images are composed offine lines, even the apparatus whose output is small can project withsufficient brightness.

As described above, the image projection apparatus according to thepresent invention comprises the laser light source for generating thelight of diffused laser beams, the condenser for converting the light ofdiffused laser beams to the light of parallel laser beams and thehologram plate which is irradiated with the light of parallel laserbeams. Because the condenser is integrated with the hologram plate intoone body unit in the above image projection apparatus, even if thehologram plate is detached from the laser diode, there can be removedsuch a risk that a man as the object may feel discomfort due to thedazzling light of parallel laser beams.

Moreover, the above-mentioned camera apparatus includes the imageprojection apparatus which is comprised of the laser light source forgenerating the light of diffused laser beams, the condenser forconverting the light of diffused laser beams to the light of parallellaser beams and the hologram plate irradiated with the light of parallellaser beams, and in which the condenser is integrated with the hologramplate into one body single unit. Thus, by projecting onto the object thehologram reproduced image is which is obtained by applying the light ofparallel laser beams to the hologram plate, the hologram reproducedimage with sufficient contrast can be projected onto the object, wherebysatisfactory focusing can be performed. At the same time, even if thehologram plate is detached from the laser diode, there can be removedthe risk that a man as the object may feel discomfort due to thedazzling light of parallel laser beams.

As described above, according to the present invention, the focusing caneasily be adjusted when a user takes a picture in the dark or the like.The present invention is not limited to the above-described embodimentand various modifications can be made without departing from the spiritof the present invention.

Thus, according to the present invention, because the image projectionapparatus includes the laser light source for generating light of laserbeams and the hologram plate and the hologram reproduced image isprojected onto the object, which is obtained by applying the light oflaser beams to the hologram plate, the hologram reproduced image can beprojected onto the object with sufficient contrast with small powerconsumption and satisfactory focusing can be performed. At the sametime, this apparatus can easily be incorporated into , for example, asmall electronic still camera.

Moreover, according to the present invention, because the auto focusingoperation is carried out using the hologram reproduced image projectedonto the object, an extremely satisfactory AF operation can be carriedout.

Moreover, according to the present invention, because the imageprojection apparatus includes the operation means for projecting thehologram reproduced image in the manual focusing operation, the user canexecute an extremely good manual focusing operation by visuallyconfirming the hologram reproduced image, and this hologram reproducedimage can never hinder the user from taking a picture.

Furthermore, according to the present invention, because the imageprojection apparatus includes the laser light source for generating thelight of diffused laser beams, the condenser for converting the light ofdiffused laser beams to the light of parallel laser beams and thehologram plate which is irradiated with the light of parallel laserbeams, and the condenser and the hologram plate are integrated with eachother into one body unit, even if the hologram plate is detached fromthe laser diode, it will be possible to remove the risk that a man asthe object may feel discomfort due to the dazzling light of parallellaser beams.

Moreover, according to the present invention, because the hologramreproduced image is projected onto the object, which is obtained byapplying the light of parallel laser beams to the hologram plate,focusing can be carried out satisfactorily by projecting the hologramreproduced image with sufficient contrast onto the object. At the sametime, even if the hologram plate is detached from the laser diode, itwill be possible to remove the risk that a man as the object may feeldiscomfort due to the dazzling light of parallel laser beams.

Moreover, according to the present invention, because the auto focusingoperation is carried out using the hologram reproduced image projectedonto the object, the extremely good AF operation can be carried out. Atthe same time, even if the hologram plate is detached from the laserdiode, it will be possible to remove the risk that a man as the objectmay feel discomfort due to the dazzling light of parallel laser beams.

Furthermore, according to the present invention, because theabove-mentioned pattern shown in FIG. 4 is employed, even if theposition of the view point is moved under the respective projectionangles, no heat is produced beyond the safety standards limit, and thesubstantial space between the segments can be reduced by the distanceequal to half of the length of the segment. Thus, even if the opticalaxis of the camera lens does not coincide with the center of theprojected image pattern, it is possible to remove such a risk that astate in which no segment is captured within the detection range mayhappen.

Moreover, according to the present invention, because the central lightspot is eliminated from a predetermined number of the light spotsforming the first segment, the luminance of the central light spot ofthe first segment can be prevented from being increased due to thezero-order light, and hence the satisfactory detection can be carriedout.

Furthermore, the present invention includes the laser light source forgenerating the light of laser beams and is arranged so that the laserlight source may be stopped from generating the light of laser beams fora fixed time period or longer, provided that the laser light sourcecontinues emitting the light of laser beams over a predetermined timeperiod. Thus, when the application of the light of laser beams to theobject continues, the output of the apparatus can be prevented fromfalling due to produced heat or the like. Therefore, it is possible todispense with the radiator plate and the like which has been used so faras the prior-art countermeasure against heat generation.

Moreover, according to the present invention, because the hologramreproduced image is projected onto the object, which is obtained byapplying the light of laser beams to the arbitrary hologram plate, thehologram reproduced image with sufficient contrast can be projected ontothe object by small power consumption, whereby satisfactory focusing canbe carried out. At the same time, this apparatus can easily beincorporated into a small electronic still camera and the like.

Furthermore, according to the present invention, the laser driveapparatus including the laser light source for generating the light oflaser beams, the means for adjusting the quantity of light of laserbeams and the camera means further comprises the means for storingtherein the adjustment value found according to the output of the camerameans which takes an image after projecting the light of laser beams.Thus, the output of the laser light source as well as the sensitivity ofthe camera means is adjusted by adjusting the quantity of light of thelaser beams based upon the stored adjustment value, thus enabling suchadjustment that absorbs the dispersions of both the sensitivity ofcamera means and the output of laser light source.

Moreover, according to the present invention, the hologram reproducedimage with sufficient contrast can be projected onto the object withsmall power consumption by projecting onto the object the hologramreproduced image which is obtained by applying the light of laser beamsto the hologram plate, so that satisfactory focusing can be carried out.At the same time, this apparatus can easily be incorporated into, forexample, a small electronic still camera.

Moreover, according to the present invention, because the quantity oflight of laser beams is adjusted based upon the automatic exposuredetected value detected from the video signal obtained by the camerameans, the circuit can be diverted to the existing camera apparatus sothat the quantity of light of the laser beams may be adjustedsatisfactorily.

Moreover, according to the present invention, because the quantity oflight of laser beams is adjusted based upon the contrast detected valuedetected from the video signal obtained by the camera means, the circuitcan be diverted to the existing camera apparatus so that the quantity oflight of laser beams may be adjusted satisfactorily.

Furthermore, according to the present invention, because the apparatusincludes the laser light source for generating the light of laser beamsand the monitor means for detecting the light of laser beams and isarranged so that the laser light source may be stopped from generatingthe light of laser beams on condition that the output of the monitormeans exceeds an arbitrary tolerance limit, it is possible to remove therisk that the laser light source may be broken or less durable owing toabnormal driving of the laser light source.

Moreover, according to the present invention, because the hologramreproduced image with sufficient contrast can be projected onto theobject with small power consumption by projecting onto the object thehologram reproduced image obtained by applying the light of laser beamsto an arbitrary hologram plate, satisfactory focusing can be done. Atthe same time, this apparatus can easily be incorporated into a smallelectronic still camera, and the like.

Furthermore, according to the present invention, the laser driveapparatus includes the laser light source for generating the light oflaser beams and the means for adjusting the quantity of light of laserbeams and is designed to adjust the quantity of light of laser beams bydriving the laser light source according to the pulse signal having thearbitrary pulse width. Thus, the quantity of light of laser beams can beadjusted satisfactorily and also can be adjusted satisfactorilydepending on the presence or absence of the built-in flash device. Atthe same time, it is possible to remove the risk that the laser lightsource may be broken or degraded in durability.

Moreover, the present invention includes an arbitrary lighting means andadjusts the quantity of light of laser beams by controlling the pulsewidth of the pulse signal according to in response to the quantity oflight of the lighting means. Thus, satisfactory adjustment of thequantity of light can be made depending on whether the built-in flashdevice is used or not.

Moreover, according to the present invention, because there is providedthe means for stopping the laser light source from generating the lightof laser beams when the means for adjusting the quantity of light of thelaser beams malfunctions, it is possible to remove the risk that thelaser light source may be broken or degraded in durability.

Furthermore, according to the present invention, because the hologramreproduced image is projected onto the object, which is obtained usingthe laser light source and the hologram plate, the hologram reproducedimage with sufficient contrast can be projected onto the object withsmall power consumption, and satisfactory focusing can be carried out inthe auto focus mode of the contrast detection system or in the manualfocus mode. At the same time, this apparatus can easily be incorporatedinto, for example, a small electronic still camera.

Moreover, according to the present invention, because the auto focusingoperation is performed by using the projected image of the hologramreproduced image projected onto the object; there can be performed theextremely satisfactory AF operation.

Moreover, according to the present invention, because the apparatusincludes the operation means for projecting the hologram reproducedimage in the manual focus mode, the user can execute the extremelysatisfactory manual focusing operation by visually confirming thehologram reproduced image, and this hologram reproduced image will neverhinder the user from taking a picture.

Moreover, according to the present invention, the laser light source isstopped from generating the light of laser beams for a fixed time periodor longer on condition that the duration in which the laser light sourcecontinues emitting the light of laser beams exceeds the predeterminedtime period. Thus, when the laser light source continues emitting thelight of laser beams for example, the output of the apparatus can beprevented from falling due to produced heat and the like, so that theradiator plate or the like that has so far been used as the conventionalcountermeasure against produced heat can be unnecessary.

Moreover, according to the present invention, the apparatus includes themeans for adjusting the quantity of light of laser beams, the camerameans and the means for storing therein the adjustment value founddepending on the output of the camera means which takes an image afterprojecting the light of laser beams. Therefore, the output of the laserlight source is adjusted together with the sensitivity of the camerameans by adjusting the quantity of light of laser beams based upon theabove-mentioned adjustment value thus stored, and hence there is carriedout the adjustment which can absorb dispersions of both the output oflaser light source and the sensitivity of the camera means.

Moreover, according to the present invention, because the quantity oflight of laser beams is adjusted based upon the automatic exposuredetected value detected from the video signal obtained when the usertakes a picture by the camera means, the circuit can be diverted to theexisting camera apparatus for satisfactory adjustment of the quantity oflight of laser beams.

Moreover, according to the present invention, because the quantity oflight of laser beams is adjusted based upon the contrast detected valuedetected from the video signal obtained when the user takes a picture bythe camera means, the circuit can be diverted to the existing cameraapparatus for satisfactory adjustment of the quantity of light of laserbeams.

Moreover, according to the present invention, because the apparatusincludes the monitor means for detecting the light of laser beams andthe laser light source is stopped from generating the light of laserbeams on condition that the output of the monitor means exceeds anarbitrary tolerance limit, there can be removed the risk that the laserlight source may be broken or degraded in durability owing to abnormaldriving of the laser light source.

Moreover, according to the present invention, because the apparatusincludes the means for adjusting the quantity of light of laser beamsand this means adjusts the quantity of light of laser beams by drivingthe laser light source with the pulse signal having an arbitrary pulsewidth, not only the quantity of light of laser beams can be adjustedsatisfactorily, but also the quantity of light of laser beams can beadjusted depending on whether the built-in flash device is used or not.Thus, there can be removed the risk laser light source will be broken orthat the degraded in durability.

Moreover, according to the present invention, because the apparatusfurther includes an arbitrary lighting means and adjusts the quantity oflight of laser beams by controlling the pulse width according to thequantity of light of the lighting means, satisfactory adjustment of thequantity of light of laser beams can be made depending on whether thebuilt-in flash device is used or not.

Moreover, according to the present invention, because the apparatusincludes the means for stopping the laser light source from generatingthe light of laser beams when the means for adjusting the quantity oflight of laser beams malfunctions, it is possible to remove the riskthat the laser light source will be broken or less durable.

Furthermore, according to the present invention, because the hologramreproduced image, which is obtained by using the laser light source andthe hologram plate, is projected onto the object and this hologram plateis integrated with the condenser for converting the light of laser beamsinto one body unit, the hologram reproduced image with sufficientcontrast can be projected onto the object so that satisfactory focusingmay be made. At the same time, even if the hologram plate is detachedfrom the laser diode, it will be possible to remove such a risk that aman as the object may feel discomfort due to the dazzling light of laserbeams.

Moreover, according to the present invention, because the auto focusingoperation is performed by using the projected image of the hologramreproduced image projected onto the object, the extremely good AFoperation can be carried out.

Furthermore, according to the present invention, because the apparatusincludes the operation means for projecting the hologram reproducedimage in the manual focus mode, a user can execute the extremely goodmanual focusing operation by visually confirming the hologram reproducedimage. Then, this hologram reproduced image will never hinder the userfrom taking a picture.

As described above, when a user takes a picture by a still camera, forexample, in the dark, it is very difficult for the user to focus on theobject in the auto focus mode of the contrast detection system or in themanual focus mode. On the other hand, the conventional camera apparatususing the auxiliary floodlight cannot focus on the object sufficiently.Moreover, because this apparatus has large power consumption, it cannotbe incorporated into a small electronic still camera and the like. Inaddition, when the hologram plate is detached from the laser diode,there is the risk that a man as the object may feel uncomfortable verymuch if he sees the dazzling light of parallel laser beams. According tothe present invention, these problems can be overcome with ease.

1. An image projection apparatus that is used with a camera apparatusand has a function to project onto an object a hologram reproduced imagethat is obtained by applying light of laser beams to a hologram plate,said image projection apparatus comprising: a laser light source forgenerating light of diffused laser beams; a lens for converting saidlight of diffused laser beams to light of parallel laser beams; and saidhologram plate irradiated with said light of parallel laser beams,wherein said lens is integrated with said hologram plate into one bodyunit.
 2. A projection image pattern that is projected by an imageprojection apparatus that is used with a camera apparatus, possesses afunction to project onto an object a hologram reproduced image that isobtained by applying light of laser beams to a hologram plate, and iscomprised of a laser light source for generating said light of laserbeams and said hologram plate, said projection image pattern beingcomposed of at least part of first to fifth segments, that are comprisedof one or a plurality of segments, each segment including apredetermined number of light spots arrayed in a straight line, whereinsaid first segment is provided in the center of a projected image at anangle of approximately 45 degrees with horizontal and vertical axes ofan image pickup plane; four said second segments are provided, at rightangles with said first segment, at each vertex of a square thatcircumscribes a circle centered at the center of said first segment andhas a predetermined length of diameter; eight said third segments areprovided, in parallel with said first segment, at each vertex and ateach vertex and at a midpoint in each side of a square thatcircumscribes a circle centered at the center of said first segment andhas a diameter twice the predetermined length; twelve said fourthsegments are provided, at right angles with said first segment, at eachvertex and at points trisecting each side of a square that circumscribesa circle centered at the center of said first segment and has a diameterthree times the predetermined length; four said fifth segments areprovided, in parallel with said first segment, at a midpoint of eachside of a square that circumscribes a circle centered at the center ofsaid first segment and has a diameter four times the predeterminedlength.
 3. A projection image pattern according to claim 2, wherein thecentral light spot is removed from said predetermined number of lightspots forming said first segment.
 4. A camera apparatus comprising animage projection apparatus including: a laser light source forgenerating light of diffused laser beams; a lens for converting saidlight of diffused laser beams to light of parallel laser beams; and ahologram plate irradiated with said light of parallel laser beams andintegrated with said lens into one body unit, wherein said imageprojection apparatus projects onto an object a hologram reproduced imagethat is obtained by applying said light of parallel laser beams to saidhologram plate, and said camera apparatus performs an auto focusingoperation by using a projected image of said hologram reproduced imageprojected onto said object.
 5. A camera apparatus comprising an imageprojection apparatus including: a laser light source for generatinglight of diffused laser beams; a lens for converting said light ofdiffused laser beams to light of parallel laser beams; and a hologramplate irradiated with said light of parallel laser beams and integratedwith said lens into one body unit, wherein said image projectionapparatus projects onto an object a hologram reproduced image that isobtained by applying said light of laser beams to said hologram plate;and operation means for projecting said hologram reproduced image in amanual focus mode is provided.